1. Field of the Invention
The present invention relates to a print producing method and a print producing apparatus, and more specifically, to a print producing method and a print producing apparatus which control the gloss of an image or the like in a print.
2. Description of the Related Art
There are now various types of printing apparatuses, by which prints are obtained to be different in the impression of the gloss of an image or the like therein depending on the type of the printing apparatus. With an electro-photographic method using toner as a color material or a thermal transfer method using ink ribbons as a color material, basically layers of these color materials are formed on a surface of a printing medium to provide a specified smoothness. This makes a printed image glossy.
On the other hand, printing apparatuses of an ink jet method using liquid ink are becoming rapidly popular, for such reasons as the easiness with which they can be handled, in applications for outputting information or images from various devices including information processing devices. The apparatuses of the ink jet method can easily form multicolor images. Furthermore, in terms of printing grades, prints provided by these apparatuses can easily stand comparison with multicolor prints based on a plate making method and printed images based on a color photography method. Accordingly, these apparatuses are applied even to the field of full color image printing.
With the ink jet method, ink permeates a printing medium to form an image and basically does not form any layers. Accordingly, printed images provided by this method are less glossy than those provided by other methods of fixing color material layers to the surface of a printing medium.
Printing medium provided with a coat layer composed of an alumina hydrate of a boehmite structure is disclosed in, for example, U.S. Pat. Nos. 4,879,166, 5,104,730, Japanese Patent Application Laid-open No. 2-276670 (1990), Japanese Patent Application Laid-open No. 4-037576 (1992), and Japanese Patent Application Laid-open No. 5-032037 (1993). These printing media provided with a coat layer composed of an alumina hydrate have the advantageous described below. Since the alumina hydrate has positive charges, ink dyes are firmly fixed to these printing media, resulting in well-colored images. Further, these printing media are more preferable than conventional printing media in terms of image quality, notably the quality of full color images as well as gloss. Thus, images as glossy as silver salt photographs can be obtained by applying, for example, dye-based ink to a printing medium provided with gloss by being coated with the alumina hydrate.
On the other hand, there have been various demands for printed images in connection with the gloss described above. Some demand is that images are printed with arranging both glossy and non-glossy parts within the same printing medium rather than making the entire printing medium uniformly glossy as described in the above documents. For example, during the recent business discussions on real estates, relevant buildings or rooms created by CG (Computer Graphics) are often viewed on a WEB site or a monitor. If any of the materials of a building displayed on the monitor is expressed by gloss, when this building is printed on a printing medium, the gloss may not be reproduced. Thus, the buildings or rooms may not be conveniently checked using this printed medium. Further, in the field of dress design, the expression of impressions of materials is important. Printouts in this field create a problem similar to that described above. This is because when a printing medium is printed, the degree of gloss on this printing medium is uniform. With a printing apparatus that can freely vary the degree of gloss even within the same printing medium, even the impressions of materials can be properly expressed. For example, in online shopping, which is expected to become popular, with a printing apparatus that can faithfully express the materials of an article displayed on a monitor, including the gloss of the materials, it is obvious that this apparatus can be conveniently used to check the article.
In this regard, the assignee of this application has proposed in Japanese Patent Application Laid-open No. 5-019660 (1993) an image forming apparatus that can partly vary the degree of gloss within the same printing media. More specifically, this application describes an arrangement for fixing a toner image transferred to a printing medium wherein a fixing temperature is varied in a direction in which a printing medium is conveyed, to vary the degree of gloss among the areas of the printing medium in this direction. Alternatively, in this arrangement, a thermal head is divided in association with the areas of the printing medium and the fixing temperature is varied among the pieces into which the head is divided, to vary the degree of gloss. This document also describes the variation of the degree of gloss among a plurality of levels based on the control of the fixing temperature.
Further, for a thermal transfer apparatus, Japanese Patent Application Laid-open No. 2001-212996 describes a similar proposal. This document describes the transfer of an overcoat layer to a printing medium on which an image has been formed using ink ribbons. In this document, the transfer temperature of the thermal head is varied between glossy parts and non-glossy parts, to vary partly the degree of gloss within the same printing medium.
Furthermore, Japanese Patent Application Laid-open No. 5-208508 (1993) (Paragraphs 0048 to 0055 and FIGS. 13 to 15) discloses a thermal transfer-based printing technique similar to that of Japanese Patent Application Laid-open No. 2001-212996. This document also describes a solid ink jet method using colorless or transparent hot-melt ink wherein gloss is provided by forming a layer on an image printed on a printing medium using the liquid ink.
However, it is impossible to employ the technique disclosed in Japanese Patent Application Laid-open No. 5-019660 (1993), Japanese Patent Application Laid-open No. 2001-212996, or Japanese Patent Application Laid-open No. 5-208508 (1993), described above, for printed images based on the ink jet method, which is currently most popular, or employing these techniques involves difficulties.
Specifically, the technique of controlling the fixing temperature to vary the degree of gloss as disclosed in Japanese Patent Application Laid-open No. 5-019660 (1993) is uniquely applicable to toner as a color material but not to printing media already printed using ink.
Further, the techniques disclosed in Japanese Patent Application Laid-open No. 2001-212996 and Japanese Patent Application Laid-open No. 5-208508 (1993) form a layer on a printing medium which is separate from a color material. To allow an ink-jet-based printing apparatus to provide such a layer, it is necessary to provide a separate apparatus for this purpose. This complicates the configuration of the printing apparatus. More specifically, Japanese Patent Application Laid-open No. 2001-212996 has only to provide an extra ribbon for an overcoat layer and allows a thermal head for printing to be used for thermal transfer without modifying the thermal head. Accordingly, the configuration of the printing apparatus is not complicated. As opposed to this, the ink jet method requires a separate thermal head and the like. This also applies to the arrangement disclosed in Japanese Patent Application Laid-open No. 5-208508 (1993). For example, as shown in FIG. 15 of this document, it is necessary to provide two head scanning mechanisms for printing and for layer formation respectively. This may complicate the configuration of the printing apparatus and increase its size. Further, with the arrangement disclosed in this document, a head for layer formation melts a solid and then ejects the resultant liquid. Accordingly, one printing apparatus has two heads for the respective methods and thus has a complicated configuration and an increased size. Further, a control arrangement for ejections from the heads is complicated.
Furthermore, if the technique disclosed in Japanese Patent Application Laid-open No. 2001-212996, or Japanese Patent Application Laid-open No. 5-208508 (1993) is applied to the ink jet method, various advantages of the inkjet method may be impaired, such as the easiness with which the ink jet-based printing apparatus can be handled.
Further, for images displayed on a monitor or photographed by a camera, their gloss is not uniform. In most cases, these images each have a plurality of degrees of gloss. Thus, if these images are printed, it is desirable to be able to express plural degrees of gloss and faithfully reproduce the images displayed on the monitor or the like. However, Japanese Patent Application Laid-open No. 2001-212996 and Japanese Patent Application Laid-open No. 5-208508 (1993), described above, simply sets the presence or absence of gloss by forming or not forming a layer, respectively. Consequently, plural degrees of gloss cannot be obtained. In this regard, Japanese Patent Application Laid-open No. 5-019660 (1993) describes the method of varying the fixing temperature and thus the degree of gloss among a plurality of levels. However, the mechanism of this method is different from that of the apparatus that creates gloss by forming a layer. Consequently, it cannot be applied to ink jet-based printing.
On the other hand, in the field of ink jet printing, the ability to preserve an image in a printed matter is a relatively important object. Printed images based on the ink jet method are likely to be degraded by a trace of ozone present in the atmosphere. Accordingly, the grade of images observed immediately after printing may not be maintained for a long time. In such a case, the value of the prints may decrease.